1. Field of Invention
The present invention relates to a gene gun system. More particularly, the present invention relates to a gene gun system and the application of the gene gun system for gene transformation, wherein under a low pressure, the gene gun system using a gas is able to accelerate the biological material containing solution to a high speed, so that the biological materials penetrate through the cell membrane/wall or skin of a animal, without using metal particle carriers and gene transformation is accomplished with only low pressure.
2. Description of Related Art
Following the discovery of the genetic materials and rapid developments in genetics, scientists now can skillfully practice genetic engineering technology, for example, introducing foreign genes to control the natures of a cell or even an organism. It has been widely applied in basic scientific studies and in improvements of agricultural products that heterologous genetic materials, such as DNAs, are transferred to the host cells in order to change the biological characteristics and morphology. For instance, genetic engineering helps to improve the insect resistance, the frost resistance or the nutrient compositions in agricultural products. In recent years, the gene transformation technology, in the forms of gene therapy or gene vaccines, has been applied in treating human diseases. Due to the successful application of the gene transformation technology in the medical field, clinical treatments of quite a few genetic diseases including cancers have significant breakthroughs.
Gene transformation can be conducted in several different approaches and the earliest approach is to use bacterial plasmids or viral vectors as medium carriers for delivering genes into the cytoplasma of the animal or plant cells. Though constantly developed and improved, it is difficult to overlook the side effects, including non-specific immune responses and genetic recombination, of the bacterial plasmids or viral vectors and the resultant risks when applied in medical treatments. On the other hand, free of using bacterial or viral carriers, other physical or mechanical approaches of gene transformation, such as, electro-perforation and micro-injection, can avoid the side effects of these carriers and be applied for therapeutic purposes. However, the stability and success rate are low and the operation is laborious.
In recent years, gene transformation using a physical approach has been applied in empirical practices. The physical approach, particle gun, is to accelerate gold particles carrying the biological materials (e.g. DNAs) into the cells for gene transformation or gene transfer. Particle gun is also applicable to the research and development of other fields, for example, plants, mammalian somatic cells, gene therapy, and the recently developed DNA vaccination.
The particle gun system uses DNA-coated gold particles within a sample cartridge and a gas to accelerate the tube based on the high pressure shock wave principle. When a preset high pressure is reached in the pressurized chamber, the sample cartridge having DNA-coated particles is accelerated by a resulting shock wave into a stopping screen. The DNA-coated particles continue to accelerate to enter the target tissue due to the inertia effect. A major disadvantage of the aforementioned methods is the loud noise resulting from the shock wave. The high speed and high pressure gas that is generated by the shock wave also causes cell deaths. Moreover, the gas used in the conventional particle gun technique employs the expensive helium gas and costly gold particles are required as carriers.
Although it is feasible to use particle gun using the gene carrying gold particles, the gold particles regularly cause damages to the cells or the interactions between the metal particles and the carried biological materials induce structural changes of the biological materials, thus hampering the clinical effects. Moreover, the operation of the particle gun is inconvenient to the user, because the preparation of the DNA-coated gold particles is complicated and troublesome. For therapeutic purposes, an effective and convenient gene delivery tool is needed for specific attenuated vaccines expressed through the epidermal tissues, virions for gene therapy or reagents for clinical tests. Especially, this gene delivery tool can dependably deliver the genetic or biological materials without causing significant variations.